Field of the Invention
The present invention relates to a machine tool spindle device, and more specifically, relates to a spindle device equipped with a system for supplying coolant to a spindle bearing part, a system for supplying coolant to a processing point, and a system for supplying purge air to a tapered bore of a tool holder lock.
Description of the Related Art
A machine tool spindle device has a constitution with the spindle installed so as to be freely rotatable inside a spindle head, and with a draw bar installed inside the spindle energized in the tool holder locking direction by a disc spring. With this spindle device, when thermal expansion in the radial direction of the spindle becomes large, the durability of the spindle bearing decreases, so to prevent this, conventionally, the spindle is cooled, coolant is supplied to the processing point, and chips adhered to the tapered bore of the tool holder locking are removed.
For example, the disc spring arrangement space or draw bar center hole are used as flow paths for coolant or coolant as disclosed by Japanese Patent Application Laid-Open Publication Nos. H07-024687, H01-092048, and H10-080839. Further, an air passage is provided to communicate from the spindle side surface to the tapered bore as disclosed by, for example, Japanese Patent Application Laid-Open Publication No. H07-024687. Further, a washing passage is branched so as to have communication from the coolant flow path of the draw bar center hole to the tapered bore as disclosed by, for example, Japanese Patent Application Laid-Open Publication Nos. 2007-307651 and 2007-307679.
With the machine tool spindle device, it is preferable to provide passages for three systems including for coolant for cooling the spindle bearing part, coolant for cooling the processing point, and air for removing chips. By combining the constitutions noted in each of the publications noted above, it is possible to realize a spindle device equipped with the three system passages. However, there is concern about the spindle device becoming larger due to issues with the combined structure.
The description herein of advantages and disadvantages of various features, embodiments, methods, and apparatus disclosed in other publications is in no way intended to limit the present invention. For example, certain features of the preferred described embodiments of the invention may be capable of overcoming certain disadvantages and/or providing certain advantages, such as, e.g., disadvantages and/or advantages discussed herein, while retaining some or all of the features, embodiments, methods, and apparatus disclosed therein.